code: def grad_tlogpdf_df(x, df, loc, scale):
      y = (x - loc) / scale
      return 0.5 * (
          (y**2 * (df + 1)) / (df * (y**2 + df))
          - np.log(y**2 / df + 1)
          - 1.0 / df
          - psi(df / 2.0)
          + psi((df + 1) / 2.0)
      )
  
file_path: autograd/autograd/scipy/stats/t.py
imports: from __future__ import absolute_import
  import scipy.stats
  import autograd.numpy
  from autograd.extend import primitive, defvjp
  from autograd.numpy.numpy_vjps import unbroadcast_f
  from autograd.scipy.special import psi
label_desc: Use image node_id 5 for calling a global function with example usage: grad_tlogpdf_df(x, df, loc, scale) and returns: unknown